Abstract: Friedman viewed that the number of bidders in bidding submit Poisson Distribution. On the aboue assumption, this paper studies reservation value setting and draws conclusions that reservation value has no pertinence with the expected number of bidders while the expected number of bidders affect expected revenue of the auctioneer. Meanwhile this paper gets a formula to calculate reservation value, thus brings forward a way for design of bidding meechanism, which further approaches actual conditions.